Method of reaction in water catalyzed by Lewis acid

Abstract

A reaction method by a novel Lewis acid catalyst stable in water for organic synthesis by using a metal compound stable in water and functioning as a Lewis acid catalyst and using water as apart or all of a solvent, the metal ion of the metal compound having a hydrolysis constant (pKh) of: 4.3<=pKh<=10.1 and a water exchange rate constant (WERC) of 3.2x106M-1sec-1 or more.

What is claimed is:  
     
       1. A method of conducting a Mannich reaction, an allylation reaction, or an aldol reaction in water catalyzed by a Lewis acid, which consists of conducting the reaction using a metal compound stable in water and functioning as a Lewis acid and employing water as a part or all of a solvent, wherein the hydrolysis constant (pKh) of a metal ion of the metal compound is within a range: 4.3≦pKh≦10.1 and the water exchange rate constant (WERC) thereof is 3.2×10 6 M 1 sec −1  or more, and wherein the metal ion is iron (II) ion, copper (II) ion, or lead (II) ion. 
     
     
       2. The method as defined in  claim 1 , wherein the metal compound is a trifluoromethane sulfonate or perchlorate of the metal ion. 
     
     
       3. A method of conducting a Mannich reaction, an allylation reaction or an aldol reaction in water catalyzed by a Lewis acid, which consists of conducting the reaction using a metal compound stable in water and functioning as a Lewis acid and employing water as a part or all of a solvent, wherein the metal compound includes a metal ion which is iron (II) ion, copper (II) ion, or lead (II) ion. 
     
     
       4. A method of identifying an aqueous system Lewis acid catalyst, which consists of testing metal compounds, and identifying a metal compound which is stable in water and functions as a Lewis acid, wherein the hydrolysis constant (pKh) of a metal ion of the metal compound is within a range: 4.3≦pKh≦10.1 and the water exchange rate constant (WERC) thereof is 3.2×10 6 M −1 sec −1  or more.